Human Respiratory Adenovirus Isolation,Typing,and Penton,Hexon And Fiber Molecular Evolution Studies In Wuhan City

Background:Human adenovirus(HAdV)is a pathogen that causes a wide spectrum of diseases,which include acute respiratory diseases,epidemic keratoconjunctivitis,gastrointestinal diseases and adenoviral pneumonia.Human adenoviruses has been classified into 7 species(A to G)and more than 103 types.HAdV-3,HAdV-4,and HAdV-7 often cause outbreaks of respiratory infections,and HAdV-55 often causes community-acquired pneumonia and death.Traditional serological methods and molecular typing methods are the two main identification methods.Due to the time-consuming,expensive and false positives of serological methods.Molecular typing has become the current mainstream adenovirus identification method.Due to the recombination phenomenon of adenovirus,this study conducted a typing and molecular evolution study on the Penton,Hexon and Fiber genes of respiratory adenovirus isolated in Wuhan city,providing a new HAdV detection method.Objective:we aimed to understand the prevalence of human respiratory adenovirus in infants and young children in central China and analyze the evolution of Penton,Hexon and Fiber genes of adenovirus,which provides a theoretical guidance for human adenovirus prevention and vaccine research.In view of the adenovirus recombination phenomenon,we create a novel adenovirus identification method for Penton,Hexon and Fiber gene typing.Methods:(1)In this study,adenovirus was isolated from A549 cells using the collected samples of children's throat swabs;(2)Real-time fluorescence quantitative PCR was used to identify the isolation of adenovirus;(3)HAdV genotyping was performed by PCR amplification and sequencing of the Penton,Hexon and Fiber gene;(4)Using multi-sequence alignment and phylogenetic tree analysis to conduct molecular evolution research on Penton,Hexon and Fiber.Results:(1)In this study,we had obtained 48 human adenovirus strains,covering HAdV-B,HAdV-C and HAdV-E species.HAdV-3(47.9%)and HAdV-7(43.7%)were the two major types,followed by HAdV-4(4.2%),HAdV-55(2.1%)and HAdV-6(2.1%);(2)According to the homology analysis of the nucleic acid sequence of the Penton,Hexon and Fiber genes of the HAdV-3 isolate,the HAdV-3 strains isolated this time belong to the genotype HAdV-3a51;in the same way,the HAdV-7 strains belongs to the genotype HAdV-7d;HAdV-4 isolate belongs to the genotype HAdV-4a1.Conclusion:Predominant types among children in Whhan city were HAdV-3 and HAdV-7,which were mostly associated with respiratory tract infections.The children who<5 years old have a higher risk of HAdV infection.